Evaluation of the associations of interlukin‐7 genetic variants with toxicity and efficacy of immune checkpoint inhibitors: A replication study of a Japanese population, based on the findings of a European genome‐wide association study

Abstract Aim Recent genome‐wide association studies of European populations have identified rs16906115, a single‐nucleotide polymorphism in the interleukin‐7 gene, as a predictor of immune‐related adverse events (irAEs) and the therapeutic efficacy of immune checkpoint inhibitors. We evaluated this single‐nucleotide polymorphism in a Japanese population. Methods From January 2021, we stored host DNA from individuals who received various types of immune checkpoint inhibitors. From this population, we categorized 510 participants into cases (grade ≥2 irAEs) and controls (received ≥3 immune checkpoint inhibitor doses, follow‐up ≥12 weeks, no irAEs), and divided 339 hepatocellular carcinoma patients treated with atezolizumab/bevacizumab into responders and non‐responders, evaluated using the modified response evaluation criteria in solid tumors. We compared the minor allele frequencies of rs16906115 between cases and controls, and responders and non‐responders. Results In the irAE prediction analysis of 234 cases and 276 controls, the minor allele frequency was 0.244 in the case group and 0.265 in the control group. This difference is not significant. In the analysis predicting the therapeutic efficacy for hepatocellular carcinoma patients, the responders had a significantly lower minor allele frequency of 0.220, compared with 0.300 for the non‐responders ( p = 0.022). Univariate and multivariate analyses identified the minor allele homozygosity as a significant predictor of treatment response, with odds ratios of 0.292 ( p = 0.015) in the univariate analysis and 0.315 ( p = 0.023) in the multivariate analysis. Conclusions In our Japanese cohort, no association was found between the rs16906115 minor allele and irAEs or treatment efficacy. The minor allele homozygosity may be associated with a negative therapeutic outcome. Clinical trial registration UMIN Clinical Trials Registry with the number UMIN000043798.